CAJ | 학술논문

为探究奥氏体化温度和冷却速率对40Cr钢球化过程的影响,采用双相区球化退火研究了热轧态40Cr钢的球化退火行为和力学性能。奥氏体化温度从760℃提高到800℃,冷却速率从10℃·h-1上升到30℃·h-1,组织硬度随冷却速度呈V形变化,碳化物球化率随冷却速度变化正好与前者相反。奥氏体化温度为760℃,冷却速率为20℃·h-1所得到的球化组织球化率高,且碳化物细小,具有良好的冷成形性能,可大幅度缩短球化退火时间,显著提高生产效率。提出了球化退火过程中离异共析转变机制,控制好球化过程中奥氏体化温度、冷却速率及保温时间有利于离异共析转变的发生。
위탐구오씨체화온도화냉각속솔대40Cr강구화과정적영향,채용쌍상구구화퇴화연구료열알태40Cr강적구화퇴화행위화역학성능。오씨체화온도종760℃제고도800℃,냉각속솔종10℃·h-1상승도30℃·h-1,조직경도수냉각속도정V형변화,탄화물구화솔수냉각속도변화정호여전자상반。오씨체화온도위760℃,냉각속솔위20℃·h-1소득도적구화조직구화솔고,차탄화물세소,구유량호적랭성형성능,가대폭도축단구화퇴화시간,현저제고생산효솔。제출료구화퇴화과정중리이공석전변궤제,공제호구화과정중오씨체화온도、냉각속솔급보온시간유리우리이공석전변적발생。
To study the impact of austenitizing temperature and cooling rate on the spheroidizing annealing process of 40Cr steel, the spheroidizing annealing behavior and the mechanical properties of 40Cr steel were investigated by conventional intercritical annea-ling. It is found that with the austenitizing temperature between 760℃ and 800℃, the hardness varies as a “V” shape but the ce-mentite spheroidization rate changes as an inverted“V” shape with increasing cooling rate from 10℃·h-1 to 30℃·h-1 . Higher sphe-roidization level and finer carbides, which are obtained at an austenitizing temperature of 760℃ and a cooling rate of 20℃·h-1 , make the steel having a better cold formability. A divorced eutectoid transformation ( DET) reaction mechanism of the spheroidizing annea-ling process was proposed, and the occurrence of the divorced eutectoid transformation reaction depends strongly on austenitizing tem-perature, cooling rate and holding time.